For a .308 shooting 175gr Federal Gold Medal match ammo it is "about" 44 inches of vertical adjustment, if I recall correctly because it's been a while, (up) from a 100 yard zero to an approx 1000 yard zero depending on barrel length, temperature, humidity, etc, etc.
If you hit a target the size of notebook paper at all will be a minor miracle unless you dial close and then shoot some "sighters" to refine your adjustment. The standard 1000 yard target is 6 feet square with a 44" bullseye. The "X" ring is similar in size to the notebook paper so to hit it will require a rifle and ammo that will hold 1MOA at 1000 yards (about 10").
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